Sulfatide with short fatty acid dominates in astrocytes and neurons

• Published in: The FEBS journal 2006-04, Vol.273 (8), p.1782-1790
• Main Authors: Isaac, Giorgis, Pernber, Zarah, Gieselmann, Volkmar, Hansson, Elisabeth, Bergquist, Jonas, Månsson, Jan‐Eric
• Format: Article
• Language: English
• Subjects: a-deficient mice; Animals; astrocyte; Astrocytes; Astrocytes - metabolism; Astrocytes - ultrastructure; brain; Cells; Cells, Cultured; Cerebroside-Sulfatase; Cerebroside-Sulfatase - genetics; Cerebroside-Sulfatase - physiology; chemistry; Cultured; differentiation; Electron; Electrospray Ionization; Fatty Acids; Fatty Acids - metabolism; Female; genetics; Inbred C57BL; Ions; Knockout; Leukodystrophy; Leukodystrophy, Metachromatic - metabolism; Leukodystrophy, Metachromatic - pathology; Male; Mass; mass-spectrometry; Medical and Health Sciences; Medicin och hälsovetenskap; metabolism; Metachromatic; metachromatic leukodystrophy; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy; Microscopy, Electron, Transmission; Molecular Biology; Molekylärbiologi; neuron; Neurons; Neurons - metabolism; Neurons - ultrastructure; pathology; physiology; primary cultures; rat cerebellum; Spectrometry; Spectrometry, Mass, Electrospray Ionization; Spectrum analysis; stearic acid; Stearic Acids; Stearic Acids - chemistry; sulfoglycolipids; Sulfoglycosphingolipids; Sulfoglycosphingolipids - metabolism; Transmission; ultrastructure; vesicle; white-matter
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/j.1742-4658.2006.05195.x

Glycosphingolipids are located in cell membranes and the brain is especially enriched. We speculated that the subcellular location of glycosphingolipids depends on their fatty acid chain length because their sugar residues are constant, whereas fatty acid chain length can vary within the same molecule. To test this hypothesis we analysed the glycosphingolipid sulfatide, which is highly abundant in myelin and has mostly long fatty acids. We used a negative ion electrospray tandem mass spectrometry precursor ion scan to analyse the molecular species of sulfatide in cultured astrocytes and a mouse model of the human disease metachromatic leukodystrophy. In these arylsulfatase A (ASA)‐deficient mice sulfatide accumulates intracellularly in neurons and astrocytes. Immunocytochemistry was also performed on cultured astrocytes and analysed using confocal laser scanning microscopy. Analyses of the molecular species showed that cultured astrocytes contained sulfatide with a predominance of stearic acid (C18), which was located in large intracellular vesicles throughout the cell body and along the processes. The same was seen in ASA‐deficient mice, which accumulated a higher proportion (15 mol% compared with 8 mol% in control mice) of sulfatide with stearic acid. We conclude that the major fatty acid composition of sulfatide differs between white and grey matter, with neurons and astrocytes containing mostly short‐chain fatty acids with an emphasis on stearic acid. Based on our results, we speculate that the fatty acid chain length of sulfatide might determine its intracellular (short chain) or extracellular (long chain) location and thereby its functions.